CISSP Security Assessment and Testing Practice Question
This CISSP practice question tests your understanding of security assessment and testing. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
An organization is conducting a security assessment of a new web application. Which testing technique would best identify cross-site scripting (XSS) vulnerabilities?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Dynamic application security testing (DAST)
DAST (Dynamic Application Security Testing) tests the running application by simulating external attacks, including injecting malicious scripts into input fields and observing the response. This directly identifies reflected, stored, and DOM-based XSS vulnerabilities because it exercises the application's runtime behavior, where XSS payloads are executed in the browser. Unlike static analysis, DAST does not require source code access and can detect vulnerabilities that only manifest during execution.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Manual code review
Why it's wrong here
Manual review is labor-intensive and may miss subtle injection points.
✗
Static application security testing (SAST)
Why it's wrong here
SAST analyzes source code and may not detect runtime injection points like XSS.
✗
Interactive application security testing (IAST)
Why it's wrong here
IAST is a hybrid but may not be as effective as DAST for external assessments.
✓
Dynamic application security testing (DAST)
Why this is correct
DAST tests the running application and can identify XSS by simulating attacks.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose SAST (Option B) because they think source code analysis is the most thorough, but they fail to recognize that XSS is a runtime vulnerability that requires dynamic testing to confirm exploitability and context-specific behavior.
Detailed technical explanation
How to think about this question
DAST tools like OWASP ZAP or Burp Suite send crafted payloads (e.g., <script>alert(1)</script>) to input fields and analyze HTTP responses for unescaped reflections. A subtle behavior is that DAST can detect XSS in AJAX responses or WebSocket messages that static tools miss. In a real-world scenario, a DAST scan of a single-page application (SPA) can uncover DOM-based XSS by interacting with client-side JavaScript that manipulates the DOM after page load.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A SOC analyst notices unusual lateral movement in the network at 2 AM. The IR playbook dictates: identify and contain (isolate the affected machine), then eradicate (remove the malware), then recover (restore from backup), then document. Skipping containment before eradication risks the attacker regaining access. Questions like this test the sequence and rationale of incident response phases.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CISSP question in full detail.
Security Assessment and Testing — This question tests Security Assessment and Testing — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Dynamic application security testing (DAST) — DAST (Dynamic Application Security Testing) tests the running application by simulating external attacks, including injecting malicious scripts into input fields and observing the response. This directly identifies reflected, stored, and DOM-based XSS vulnerabilities because it exercises the application's runtime behavior, where XSS payloads are executed in the browser. Unlike static analysis, DAST does not require source code access and can detect vulnerabilities that only manifest during execution.
What should I do if I get this CISSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This CISSP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CISSP exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.